Hitachi, Ltd.

Koji Honami

Naoto Ueda

Motoaki Satoyama

Naohiro Fujii

Atsushi Sutoh

Takeshi Kitamura

Shinji Ogasawara

A computer system is coupled to a local storage system and a remote storage system, and comprises a data mover, and a recall size analysis unit. The recall size analysis unit uses a combination of type of the data and size of the data as a retrieval key of an access characteristics to analyze the logs of the same access characteristics and to determine a recall size for each of the access characteristics. The data mover obtains a target data corresponding to the recall size of the access characteristics of the target data from the remote storage system in a case of receiving a read request for the target data that is not stored in the local storage system.

Computer system and data access control method

A high-performance and highly-reliable snapshot management apparatus and method, and a storage system are provided that can prevent the adverse influence of overhead when they retain a multiplicity of snapshots. An operational volume is set in a storage area provided by a first storage apparatus and a plurality difference volumes are set in a storage area provided by a second storage apparatus. In response to data writing to the operational volume, difference data is saved in the difference volumes and management tables for it are created, with each snapshot being managed according to the management tables. Each management table is divided according to one or more snapshots in accordance with the snapshot creation time. The second and any following management tables store specified inheritance information to inherit the content of the preceding management tables.

Snapshot management apparatus and method, and storage system

Provided is a method of managing differential snapshots in a storage system, the storage system having a disk drive and a disk controller, the differential snapshot management method including the steps of: providing a storage area of the disk drive as a plurality of logical volumes including an operational volume and a differential volume; storing a time of update for each block in the operational volume; and judging, upon reception of a request to write in a block included in the operational volume, whether to copy data of the block in which requested data is to be written in accordance with the received write request to the differential volume, based on the time of update of the block in which requested data is to be written and a time of creation of the differential snapshot. Accordingly, it is possible to manage the differential snapshot without using a bitmap.

Method of managing time-based differential snapshot

A high-performance and highly-reliable snapshot management apparatus and method, and storage system are provided that can prevent the adverse influence of overhead when they retain a multiplicity of snapshots. An operational volume is set in a storage area provided by a first storage apparatus and a plurality difference volumes are set in a storage area provided by a second storage apparatus. In response to data writing to the operational volume, difference data is saved in the difference volumes and management tables for it are created, with each snapshot being managed according to the management tables. Each management table is divided according to one or more snapshots in accordance with the snapshot creation time. The second and any following management tables store specified inheritance information to inherit the content of the preceding management tables.

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Tokyo, Japan

Koji Honami